The court agreed. Because she had served half the sentence she was freed.

Judge Peter Crawford QC, who heard the appeal with two magistrates, told Amos she had "persistently and deliberately" refused to accept her parental obligations.

Unprecedented

But he said: "We have taken all the circumstances into account and the sentence of 60 days imprisonment - although justified in principle - we think the sentence was longer than necessary."

He made it clear to Amos that if she went back to the same sort of behaviour when she left prison she might find herself in front of him again.

Patricia Amos had been sent to prison for failing to ensure that her daughters, Emma, 15, and Jackie, 13, attended lessons at their Banbury comprehensive school.

Oxfordshire's Keith Mitchell: "Children need their education"

It was believed to be the first time magistrates had passed such a sentence on a parent under powers they gained in November 2000.

During the appeal hearing Louise Worton, for the prosecuting authorities, said Amos had repeatedly failed to ensure her children attended school and had repeatedly missed meetings with education officials.

She had also breached a parenting order obliging her to ensure the girls attended morning and afternoon registrations at their school.

Bereavement

From September 2001 to February this year, the court was told, the older daughter, Emma, had attended only 55 out of 190 school registrations - a 29% record.

Paul Reid, the barrister acting for Amos, told the court that the death of her 63-year-old mother at the family home in 1999 - where she was found by the two teenage girls - had exaggerated the problem of the children's truancy and had caused "devastation" in the family.

A letter to the court from Jennifer Wolfendene, a bereavement councillor at Holloway Prison, said: "The extreme distress experienced by this family after this woman's death became pathological."

Tough warnings

The leader of Oxfordshire County Council, Keith Mitchell, said outside the court that the judge had backed its action and it would do the same again if necessary.

"I hope this will be a warning that we mean business," he said.

"Children need their education. They only have one chance and we will do what we can to ensure they have the best chance."

A spokesperson for the Department for Education said: "Children must go to school and parents have to play their part in making sure they do.

Attendance

"We will continue to support parents who need extra help and who work with schools to tackle truancy.

"Fifty thousand young people play truant every day and it is absolutely right that we take the tough decisions to reduce this."

The children have been staying with their eldest sister on the Bretch Hill estate in Banbury.

They are believed to have been attending school regularly since the sentence.

Delays

Technically Amos served only 13 days - not the 14 which would have been half the sentence, but Holloway agreed to her release following the court hearing.

The appeal proceedings had been delayed because Amos was taken from Holloway jail to Oxford via two other courts.

The appeal court was told at midday that the Securicor van had gone to Guildford Crown Court in Surrey, then on to High Wycombe Magistrates' Court in Buckinghamshire, to drop off other prisoners.

The judge said that in his view she had been detained unlawfully in the prison van and he would be demanding a full explanation.

"It is the duty for custody authorities to produce prisoners on time for their appearance in court. I'm not aware of any legal justification for detaining a person after a time they are required to appear in court," he said.